<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			var flag=false;
			var fun=function(){
				var img=document.querySelector("img");
				var h2=document.querySelector("h2");
				if(flag){
					img.setAttribute("src","img/off.png");
					h2.innerHTML="灯灭了";
					h2.setAttribute("style","color: black");
					flag=false;
				}
				else{
					img.setAttribute("src","img/on.png");
					h2.innerHTML="灯亮了";
					h2.setAttribute("style","color: red");
					flag=true;
				}
			}
		</script>
	</head>
	<body>
		<div onclick="fun()">
			<img src="img/off.png" width="100px">
			<h2>点击开灯</h2>
			
		</div>
	</body>
</html>
